1. Field of the Invention
The present invention relates to an ultra-wide band antenna, and more particularly, to an antenna for ultra-wide band communication. Although the present invention is suitable for a wide scope of applications, it is particularly suitable for fabricating an antenna having a compact size, being light weight, and having a low fabrication cost.
2. Discussion of the Related Art
The ultra-wide band (UWB) communication is a wireless communication method, which was first developed by the United States Department of Defense in the 1960's and used for military purposes. The UWB communication has a wide frequency band, a low power consumption, and a fast transmission speed. Also, the UWB communication forms a spectrum of a level lower than that of a white noise in a code division multiple access (CDMA) communication. Thus, the listening-in or cutting-off of signals becomes difficult, thereby being suitable for maintaining security. Moreover, unlike the conventional communication system, the UWB communication system performs communication using pulses. Recently, due to such characteristics, the UWB communication has been considered to be a next generation wireless data communication method, research on which is being extensively carried out worldwide.
Due to the many advantages of the UWB communication, the UWB communication is expected to be used extensively in various systems, such as personal communication networks or home networks connecting personal computers (PC), television receivers (TV), personal digital assistants (PDA), digital versatile discs (DVD), digital cameras, and printers, which are within a close range of 10 meters (m), global positioning systems, automobile collision avoidance systems, and medical apparatuses. The current UWB communication system is currently being standardized at a vast rate, starting from the United States. Many related corporations and university research laboratories have founded a mutual technology research group called the Ultra Wideband Working Group (UWBWG), which carries out many active studies. The level of interest is also increasing in the related fields in Korea by holding diverse forums and so on.
Recently, in the United States, the Federal Communications Commission (FCC) has approved the usages of the UWB communication bandwidth ranging from 3.1 to 10.6 gigahertz (GHz), in order to eliminate radio frequency interference with the conventional mobile communication system and the global positioning system (GPS). Herein, the transmission range has also been limited to within 9 meters (m). Therefore, in the related industry, the UWB communication is being considered as a new alternative for the wireless personal area network (WPAN), and applications of the UWB communication method are being actively and extensively developed.
However, one of the most important factors in the development of the UWB communication system is the development of an ultra-wide band antenna. More specifically, the UWB communication system has many advantages, such as very high speed communication, high amount of transmission, excellent obstacle transmission, a simple structure of receiver/transmitter, low transmission power, and so on. Herein, the UWB antenna acts as an essential assembly part for representing the UWB communication system having the above-described advantages.
In order to ensure the mobility of the UWB antenna, the UWB antenna should be formed to have the characteristics of compact size, simple and easily fabrication method, and low product cost. Additionally, the UWB antenna should also have a structure having a constant impedance value independent from the corresponding frequency. Furthermore, the UWB antenna should also have little distortion in the pulse signal. However, the development of such antenna has brought about many difficulties. And, a wide range of researchers has been globally participating in the development of an ultra-wide band antenna. Recently, only a few companies, such as Skycross, Timedomain, Taiyo-Yuden, and so on, have presented their mock-up products of the UWB antenna.